1. Field of the Invention
The invention relates the formation of a plurality of buried layers more particularly using as buried layers inside a semiconductor device.
2. Description of the Prior Art
Firstly, as shown in FIG. 1A, a semiconductor substrate 101, nitride layer 102 and p.sup.+ -type 103 are provided.
Then, as shown FIG. 1B, p.sup.+ -type buried layers 103 are removed by the conventional etching.
Then, as shown in FIG. 1C, the n.sup.+ -type ions are implanted into the semiconductor substrate 101 as a plurality of n.sup.+ -type regions 104 located under the surface of the plurality of concave portions.
Next, as shown in FIG. 1D, the oxide layer 105 is deposited over the surfaces of the plurality of concave portions and the surface of the plurality of convex portions. Finally, a silicon layer 106 is formed to fill the plurality of concave portions a silicon layer and to cover the surfaces of the plurality of convex portions.